Hand truck

ABSTRACT

A hand truck having a frame two short and two long sides; a wheel and axel assembly attached to the frame; a lifting assembly extending between the two short sides; said lifting assembly comprising a frame center pole rail having an attached gear rack, a gear box movably attached to the center pole, said gear box including, a toothed that meshes with the gear rack, a worm gear having a drive shaft that meshes with the toothed pinion, wherein rotation of the drive shaft causes the worm gear to drive the pinion along the gear rack; a lift bracket attached to the gear box comprising a receiving plate with at least one slot; and at least one removable lift platform comprising a platform plate with at least one key that is securely receivable into the slot; wherein the gearbox is drivable using a power supply supplied by a user.

This application is a reissue of U.S. Pat. No. 9,233,699 issued on Jan.12, 2016.

FIELD OF THE INVENTION

The present invention relates to a hand truck. More specifically, thehand truck of the present invention includes a powered lifting/loweringfeature.

BACKGROUND

Hand trucks are well known devices used for the manual transportation ofheavy loads from one location to another location. The most common handtruck has a generally L-shaped body with wheels at the vertex of theL-shaped body and at least one handle located either around a midpointof the L-shape or near the top of the L-shape. The short leg of theL-shape is the load bearing portion of the hand truck, with the shortlet typically level with a support surface when the hand truck isupright. An object to be moved is tilted forward, the short leg isinserted underneath such object, the object is then allowed to tilt backand rest on the short leg. Then the hand truck, with supported object,is tilted backward until the center of gravity of the combination isgenerally balanced over the wheels, making otherwise bulky and heavyobjects easier to move.

Improvements to such hand-propelled vehicles have been developed overthe years. One improvement relates to providing powered lifting,lowering and transporting features. One example of such a prior artdevice is disclosed in U.S. Pat. No. 6,530,740 issued to Kim on Mar. 11,2003. Kim teaches a hand truck with an electrically operated liftingplatform. While Kim is an improvement over the prior art hand-propelledvehicles, the Kim hand truck does not fully address several problemsrelated to providing a powered hand truck device with powered features;some of which are discussed below. In addition, Kim provides noteachings related to associating an electronic module for providingautomatic features to such the system (as described later).

Thus there is a current need for new handtrucks.

SUMMARY OF THE INVENTION

Some of the objects and advantages of the invention will now be setforth in the following description, while other objects and advantagesof the invention may be obvious from the description, or may be learnedthrough practice of the invention.

Broadly speaking, a principle object of the present invention is toprovide a portable apparatus for manually transporting items with apowered lifting and lowering feature.

Another object of the invention is to provide a portable apparatus formanually transporting items comprising a powered lifting and loweringfeature, wherein said apparatus comprises a removably attachable motor,such as a hand drill or the like.

It is yet another object of the present invention is to provide a handtruck for moving heavy or bulky objects comprising: a frame having twoshort sides and two long sides; a wheel and axel assembly attached tothe frame; a lifting assembly located an intermediate position betweenthe two long sides and extending between the two short sides; saidlifting assembly comprising: a frame center pole rail having a gear rackattached thereto, a gear box movably attached to the center pole, saidgear box including, a toothed pinion, located in the movable gear box,mounted on a shaft in the gear box and meshing with the gear rack of thecenter pole, a worm gear that meshes with the toothed pinion, said wormgear including a drive shaft, wherein rotation of the drive shaft causesthe worm gear to drive the pinion along the gear rack; a lift bracketcomprising a receiving plate with at least one slot; and at least oneremovable lift platform comprising a platform plate with at least onekey that are securely receivable into the slot of the lift bracketreceiving plate.

It is yet another object of the present invention to provide the abovehand truck wherein the gearbox is drivable using a power supply suppliedby a user.

It is yet another object of the present invention to provide the abovehand truck further comprising an aperture located in the platform plateand a locking mechanism located on the lift bracket receiving plate andreceivable by the aperture located in the platform plate.

It is yet another object of the present invention to provide the abovehand truck wherein at least one of the at least one removable liftplatform includes a lift platform attached to a bottom edge of theplatform plate.

It is yet another object of the present invention to provide the abovehand truck wherein at least one of the at least one removable liftplatform includes a pair of lift bumpers attached at a top end and abottom end of the platform plate.

It is yet another object of the present invention to provide the abovehand truck wherein at least one of the at least one removable liftplatform includes a pair of lift cradles attached at a top end and abottom end of the platform plate.

It is yet another object of the present invention to provide the abovehand truck wherein at least one of the at least one removable liftplatform includes a lift platform attached to a bottom edge of theplatform plate, at least one of the at least one removable lift platformincludes a pair of lift cradles attached at a top end and a bottom endof the platform plate, and at least one of the at least one removablelift platform includes a pair of lift cradles attached at a top end anda bottom end of the platform plate.

The novel features that are considered characteristic of the inventionare set forth with particularity in the appended claims. The inventionitself, however, both as to its structure and its operation togetherwith the additional object and advantages thereof will best beunderstood from the following description of the preferred embodiment ofthe present invention when read in conjunction with the accompanyingdrawings. Unless specifically noted, it is intended that the words andphrases in the specification and claims be given the ordinary andaccustomed meaning to those of ordinary skill in the applicable art orarts. If any other meaning is intended, the specification willspecifically state that a special meaning is being applied to a word orphrase. Likewise, the use of the words “function” or “means” in theDescription of Preferred Embodiments is not intended to indicate adesire to invoke the special provision of 35 U.S.C. §112, paragraph 6 todefine the invention. To the contrary, if the provisions of 35 U.S.C.§112, paragraph 6, are sought to be invoked to define the invention(s),the claims will specifically state the phrases “means for” or “step for”and a function, without also reciting in such phrases any structure,material, or act in support of the function. Even when the claims recitea “means for” or “step for” performing a function, if they also reciteany structure, material or acts in support of that means of step, thenthe intention is not to invoke the provisions of 35 U.S.C. §112,paragraph 6. Moreover, even if the provisions of 35 U.S.C. §112,paragraph 6, are invoked to define the inventions, it is intended thatthe inventions not be limited only to the specific structure, materialor acts that are described in the preferred embodiments, but inaddition, include any and all structures, materials or acts that performthe claimed function, along with any

and all known or later-developed equivalent structures, materials oracts for performing the claimed function.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates one embodiment of the present invention.

FIG. 2 illustrates a second embodiment of the present invention.

FIG. 3 illustrates the drive mechanism of the present invention.

FIG. 4 illustrates the inner elements of the drive mechanism of thepresent invention.

FIG. 5 illustrates the strap, drive, and handle mechanisms of thepresent invention.

FIG. 6 illustrates the attachment of a first embodiment of the liftingplatform for the present invention.

FIG. 7 is an exploded view showing the lifting platform separated fromthe hand truck of the present invention.

FIG. 8 shows the attachment of the lifting platform to the hand truck ofthe present invention, the magnification illustrates how variousportions of the lifting platform line up with complementary portionslift bracket of the hand truck.

FIG. 9 illustrates the direction of movement of the keys and pop pin ofthe lift mechanism.

FIG. 10 illustrates a perspective view of the bottom half of a handtruck according to the present invention with a lifting platformattached to the hand truck.

FIG. 11 is an exploded view showing a second embodiment of the liftingplatform separated from the hand truck of the present invention.

FIG. 12 is a front perspective view of the second embodiment of thelifting platform attached to the hand truck according to the presentinvention.

FIG. 13 is a first illustration of the placement of a third embodimentof a lifting platform onto a hand truck according to the presentinvention.

FIG. 14 is a second illustration of the placement of a third embodimentof a lifting platform onto a hand truck according to the presentinvention.

FIG. 15 illustrates the use of the third lifting platform embodiment inlifting a cylindrical object, such as a water heater.

FIG. 16 illustrates a strap locking mechanism for the hand truckaccording to the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

Reference now will be made in detail to the embodiments of theinvention, one or more examples of which are set forth below. Eachexample is provided by way of explanation of the invention, notlimitation of the invention. In fact, it will be apparent to thoseskilled in the art that various modifications and variations can be madein the present invention without departing from the scope or spirit ofthe invention. For instance, features illustrated or described as partof one embodiment can be used on another embodiment to yield a stillfurther embodiment. Thus, it is intended that the present inventioncovers such modifications and variations as come within the scope of theappended claims and their equivalents. Other objects, features, andaspects of the present invention are disclosed in or may be determinedfrom the following detailed description. Repeat use of referencecharacters is intended to represent same or analogous features, elementsor steps. It is to be understood by one of ordinary skill in the artthat the present discussion is a description of exemplary embodimentsonly, and is not intended as limiting the broader aspects of the presentinvention.

For the purposes of this document two or more items are “mechanicallyassociated” by bringing them together or into relationship with eachother in any number of ways including a direct or indirect physicalconnection that may be releasable (snaps, rivets, screws, bolts, etc.)and/or movable (rotating, pivoting, oscillating, etc.) Similarly, two ormore items are “electrically associated” by bringing them together orinto relationship with each other in any number of ways including: (a) adirect, indirect, wireless, or inductive communication connection, and(b) a direct/indirect or inductive power connection. Additionally, whilethe drawings may illustrate various electronic components of a systemconnected by a single line, it will be appreciated that such lines mayrepresent one or more signal paths, power connections, electricalconnections and/or cables as required by the embodiment of interest.

While this section of the specification may contain headers, suchheaders are simply place markers and do not form a part of thespecification and are not to be used in the construction of thespecification.

While the particulars of the present invention and associated technologymay be adapted for use with any type of apparatus for manuallytransporting items, the examples discussed herein are primarily in thecontext of a hand truck/dolly structure.

Referring now to the figures, the present invention is a hand truck 1.The hand truck 1 comprises a generally rectangular frame 10 having twoshort sides 12 and two long side 14. Preferably, the frame 10 isbasically constructed from aluminum, however it could be made out ofsteel, plastic, or the like. In a most preferred embodiment, thegenerally rectangular frame 10 has square corners with upper and lowerframe corner brackets 16 made out of steel to provide additional framestrength.

Located adjacent one of the short sides 12 is a wheel and axel assembly20 comprising at least two wheel brackets 21 attached to the frame 10, awheel axel rod 22 rotationally attached to, and extending between, theat least two wheel brackets 21, and at least two wheels 24 attached toopposite ends of the wheel axel rod 22, respectively. Solid or inflatedwheels may be used in with the present invention. The preferred wheelsare those typical used on hand trucks, dollies, carts and the like.

Located at an intermediate position between the two long sides 14, andextending between the two short sides 12, is a lifting assembly 30.

The lifting assembly 30 preferably comprises a frame center pole rail 32that has an attached gear rack 34. The frame center pole 32 ispreferably a 1″ to 1½″ galvanized steel pole. The frame center pole 32is received into an upper and lower receiving 1¾″ tube brackets 33,which are mounted to the short legs 12 of the frame 10 in order tosecurely attach the frame center pole 32 to the frame 10. Preferably,the frame center pole 32 has the metal gear rack 34 welded to a backface of the frame center pole 32, however, alternate attachment meansthat are common in the arts may be used to attached the gear rack 34 tothe center pole 32.

Movably attached to the inner pole rail 32 and attached gear rack 34 isa movable gear box 36 that is drivable along the length of the liftingassembly 30 using an external drive source, such as a portable drill 100or the like. Preferably, the lifting assembly 30 further comprises anouter pole slide 38 attached to the movable gear box 36 on the oppositeside of the inner pole rail 32.

A pinion 42, located in the movable gear box 36, is mounted on a shaft44 fixed in bushings (not shown) attached to the movable gear box 36.Teeth 48 of pinion 42 mesh with the teeth 35 of the attached gear rack34. A drive shaft 50 is attached to a worm gear 52 and is mounted inbearings (not shown) fixed respectively in movable gear box 36. Rotationof the drive shaft 50 causes worm gear 52 to drive pinion 42 along thegear rack 34.

In the present invention it is critical that the gear box 36 uses a rackand pinion system in order to prevent unwanted back-drive of the gearbox 36 caused by gravity acting on the load. Because there is nounwanted back-drive, the system of the present invention does notrequire a manual brake or electromagnetic brake in order to keep theload in place once lifted.

In a preferred embodiment, the present invention does not include adrive motor attached to the hand truck 1, as is commonly found in theprior art. The preferred embodiment of the present invention utilizes anexternal drive motor that is supplied by the user, such as a cordlesspower drill 100 or the like. A rotating throttle handle 102 controls theportable electric drill trigger by a throttle control cable 104 affixedto portable drill energizing forward or reverse motion to worm gear boxmodule (not shown).

Removable lifting platforms 150 are designed to be removably attached tolift brackets 120 that are attached to the gear box 36. The lift brackethas a receiving plate 122. The receiving plate 122 preferably has atleast one, more preferably at least two and most preferably at leastfour slots 124 to receive a like number of keys 152 from a liftingplatform 150.

In a preferred embodiment, the lifting platform 150 comprises a platformplate 151 having the at least one, more preferably at least two and mostpreferably at least four keys 152 which simple slide into the receivingplate 122 attached to the gear box 36.

In order to keep the lifting platform 150 in place once the keys 152 areinserted into the receiving plate slots 124, a locking mechanism 126,such as a plunger spring loaded slide, passes through both the receivingplate 122 and at least one pin receiving aperture 154 in the platformplate 151 and locks the two together.

In a preferred embodiment, there are straps 160 used to hold liftedobjects securely in place. In a preferred embodiment, two ratchet straps161 are attached to the left side of the hand truck 1 with D-rings 162for the hooks of the straps 161 to engage to the right side of the handtruck 1.

In a preferred embodiment, there is a strap lock 170 that pivotallylocks and unlocks the straps 160. Preferably, located at one end of thestrap axis is a toothed/ratchet gear 172. A tang 174 is pivotallyattached to an end of the lift bracket 120 near the toothed gear 172 andis rotatably engagable/unengagable with the toothed gear 172. Whenengaged, the tang 174 locks the toothed gear 172, and consequently thestrap 162, into place. When the tang 174 is disengaged from the toothedgear 172, then the strap 162 is free to be wound or unwound.

In a preferred embodiment, there may be upper and lower half moon glidebrackets 126 attached to the receiving plate 122. The glide brackets 126provide upper and lower support to the receiving plate 122 as the gearbox 36 is traveling up and down the rail 32.

Located on the back side of the lifting brackets 120 are at least oneglide 128 affixed to each outer corner of the bottom of the liftingbrackets 120. These glides 128 allow the lifting brackets 120 to remainstable and glide with ease up and down the front of the dolly frame 10.In an alternate embodiment, the glides 128 may be made to rotate bymeans of a sleeve or a bearing.

In a preferred embodiment, a cordless drill chuck 51 simply slides ontothe gear box drive shaft 50. The drill chuck 51 is typically tightenedby hand, however square nut, hex head, or keyed head could be attachedto the distal end of the drive shaft 50. This would allow the drill tobe fastened to the drill with a socket attachment held in the drillchuck 51.

In order to comfortably steer the hand truck 1 according to the presentinvention, located just above a mid-point in the long sides 14 of theframe 10 are at least one, preferably two handles 60. Preferably, theseare adjustably attached to the long sides 14 such that they can beeasily placed and locked into place at a comfortable location for thedifferent users.

There are various lifting platforms 150 that may be used with the handtruck 1 of the present invention. First, all of the various embodimentsof lifting platforms 150 that are use with the present invention have aplatform plate 151 with at least one, more preferably at least two andmost preferably at least four keys 152 and at least one pin receivingaperture 154. In a first embodiment of the lifting platform 150,attached at a bottom edge of the platform plate 151 is a lift platform155. In a second embodiment of the lifting platform 150, attached at atop end and a bottom end of the platform plate 151 is a pair of liftbumpers 156. In a third embodiment of the lifting platform 150, attachedat a bottom edge of the platform plate 151 is a pair of lift cradles157.

In a most preferred embodiment, the hand truck 1 further includes awheeled kick-out 180. Preferably the kick-out 180 is pivotally attachedto about a mid-point of the long sides 14 of the frame 10. Morepreferably, the kick-out 180 also features a spring biased lockingmechanism 190 for locking the kick-out 180 to the axel rod 20 when notin use.

The preferred embodiment of the invention is described above in theDrawings and Description of Preferred Embodiments. While thesedescriptions directly describe the above embodiments, it is understoodthat those skilled in the art may conceive modifications and/orvariations to the specific embodiments shown and described herein. Anysuch modifications or variations that fall within the purview of thisdescription are intended to be included therein as well. Unlessspecifically noted, it is the intention of the inventor that the wordsand phrases in the specification and claims be given the ordinary andaccustomed meanings to those of ordinary skill in the applicable art(s).The foregoing description of a preferred embodiment and best mode of theinvention known to the applicant at the time of filing the applicationhas been presented and is intended for the purposes of illustration anddescription. It is not intended to be exhaustive or to limit theinvention to the precise form disclosed, and many modifications andvariations are possible in the light of the above teachings. Theembodiment was chosen and described in order to best explain theprinciples of the invention and its practical application and to enableothers skilled in the art to best utilize the invention in variousembodiments and with various modifications as are suited to theparticular use contemplated.

What is claimed is:
 1. A hand truck for moving heavy or bulky objectscomprising: a frame having two short sides and two long sides; a wheeland axle assembly attached to the frame; a lifting assembly located atan intermediate position between the two long sides and extendingbetween the two short sides; said lifting assembly comprising;: a framecenter pole rail having a gear rack attached thereto; a gear box movablyattached to the frame center pole rail, said gear box including: atoothed pinion, located in the movable gear box, mounted on a shaft inthe gear box and meshing with the gear rack of the frame center polerail; a worm gear that meshes with the toothed pinion, the worm gearincluding a drive shaft, wherein rotation of the drive shaft causes theworm gear to drive the pinion along the gear rack; a lift bracketcomprising a receiving plate with at least one slot; and at least oneremovable lift platform comprising a platform plate with at least onekey that are is securely receivable into the at least one slot of thelift bracket receiving plate, wherein the removable lift platformfurther comprises a pair of lift members, with one lift member attachedat a top end of the platform plate and the other lift member attached ata bottom end of the platform plate; and an aperture located in theplatform plate and a locking mechanism located on the lift bracketreceiving plate and receivable by the aperture located in the platformplate; wherein rotation of the drive shaft moves the gear box along theframe center pole rail.
 2. The hand truck according to claim 1 whereinthe gearbox is drivable using a power supply supplied by a user.
 3. Thehand truck according to claim 1 wherein the pair of lift membersincludes a pair of lift bumpers.
 4. The hand truck according to claim 1wherein the pair of lift members includes a pair of lift cradles.
 5. Thehand truck according to claim 4 further comprising: a second removablelift platform comprising a platform plate with at least one key that aresecurely receivable into the at least one slot of the lift bracketreceiving plate, wherein the removable lift platform further comprises apair of lift bumpers, with one lift bumper attached at a top end of theplatform plate and the other lift bumper attached at a bottom end of theplatform plate; whereby the hand truck can change between a pair ofbumpers and a pair of cradles.
 6. A hand truck for moving heavy or bulkyobjects comprising: a frame having two short sides and two long sides; awheel and axle assembly attached to the frame; a lifting assemblylocated at an intermediate position between the two long sides andextending between the two short sides; said lifting assembly comprising;a frame pole rail having a gear rack attached thereto, a gear boxmovably attached to the frame pole rail, said gear box including: atoothed pinion, located in the movable gear box, mounted on a shaft inthe gear box and meshing with the gear rack of the frame pole rail aworm gear that meshes with the toothed pinion, said worm gear includinga drive shaft, wherein rotation of the drive shaft causes the worm gearto drive the pinion along the gear rack; a lift bracket comprising areceiving plate with at least one slot and at least one aperture; and atleast one removable lift platform comprising a platform plate with atleast one key that are securely receivable into the at least one slot ofthe lift bracket receiving plate and a locking mechanism receivable bythe aperture located in the platform plate; wherein the platform platefurther includes a pair of lift bumpers attached at a top end and abottom end of the platform plate; wherein the gearbox is drivable usinga power supply supplied by a user.
 7. A hand truck for moving heavy orbulky objects comprising: a frame having two short sides and two longsides; a wheel and axle assembly attached to the frame; a liftingassembly located at an intermediate position between the two long sidesand extending between the two short sides; said lifting assemblycomprising; a frame center pole rail having a gear rack attachedthereto, a gear box movably attached to the frame center pole rail, saidgear box including: a toothed pinion, located in the movable gear box,mounted on a shaft in the gear box and meshing with the gear rack of theframe pole rail, a worm gear that meshes with the toothed pinion, saidworm gear including a drive shaft, wherein rotation of the drive shaftcauses the worm gear to drive the pinion along the gear rack; a liftbracket comprising a receiving plate with at least one slot and at leastone aperture; and at least one removable lift platform comprising aplatform plate with at least one key that are securely receivable intothe at least one slot of the lift bracket receiving plate and a lockingmechanism receivable by the aperture located in the platform plate,wherein the removable lift platform further includes a pair of liftcradles attached at a top end and a bottom end of a platform plate;wherein the gearbox is drivable using a power supply supplied by a user.8. A hand truck, comprising: a frame having a first end and a secondend; a wheel and axle assembly attached to the first end of the frame; agear rack supported by the frame and extending between the first andsecond ends of the frame, the gear rack including a plurality of gearteeth spaced along a length of the gear rack; a gear box movablyattached to the gear rack, said gear box including a worm gearmechanically associated with the gear teeth of the gear rack so thatrotation of the worm gear relative to the gear teeth causes the gear boxto move along a length of the gear rack; an attachment coupled to theworm gear and adapted to receive a portable, removably attachable motorto rotate the worm gear; and a lifting platform coupled to the gear boxand moveable along the length of the gear rack with the gear box;wherein the hand truck does not include a drive motor attached to it;and wherein the worm gear is positioned on a first side of the gear rackand the lifting platform is positioned on a second side of the gearrack.
 9. The hand truck of claim 8, and further comprising a driveshaft, wherein said portable removably attachable motor is a power drilland said drive shaft is adapted to receive a drill chuck to power saidlifting assembly to move said lifting platform.
 10. The hand truck ofclaim 9, wherein the power drill is a cordless drill.
 11. The hand truckof claim 9, wherein said drive shaft is arranged to rotate the worm gearto lift said lifting assembly.
 12. A system including the hand truck ofclaim 8, wherein said lifting platform is a first lifting platformhaving a horizontal platform plate and the system further comprising asecond lifting platform attachable in place of said first liftingplatform, said second lifting platform having at least one cradleadapted for receiving a cylindrical object in said cradle.
 13. A handtruck, comprising: a frame having a first end and a second end; a wheeland axle assembly attached to the first end of the frame; a liftingplatform moveable along a length of the frame; and a lifting assemblyarranged to move said lifting platform along the frame; wherein the handtruck does not include a drive motor attached to it; wherein the liftingassembly includes an attachment; wherein said attachment is adapted toreceive a portable removably attachable motor attached thereto to powersaid lifting assembly to move said lifting platform; and wherein arotatable throttle control handle is attached to the frame and controlsthe portable removably attachable motor by a throttle control cableaffixed to the portable removably attachable motor.
 14. A hand trucksystem, comprising: a hand truck having: a frame having a first end anda second end; a wheel and axle assembly attached to the first end of theframe; a lift bracket moveable along a length of the frame; a liftingassembly arranged to move the lift bracket along the frame; and a firstlifting platform attachable to the lift bracket and having a horizontalplatform plate; and a second lifting platform attachable to the liftbracket in place of said first lifting platform, said second liftingplatform having at least one cradle adapted for receiving a cylindricalobject in said cradle; wherein the lifting assembly includes a gear rackand a gear box; wherein said gear rack extends between the first andsecond ends of the frame; wherein rotation of the worm gear around anaxis of rotation causes the gear box to move along a length of the gearrack; wherein the first lifting platform is coupled to the gear box andmoveable along the length of the gear rack with the gear box; andwherein the gear box is positioned on a first side of the gear rack andthe first lifting platform is positioned on a second side of the gearrack.
 15. The hand truck system of claim 14, and further comprising astrap to securely hold objects in place on said hand truck.
 16. The handtruck system of claim 14, wherein the cylindrical object is a waterheater.
 17. The hand truck system of claim 14, wherein the first andsecond lifting platforms each have a projection arranged to be receivedwithin a slot of the lift bracket.